KR20060135493A - Honeycomb structured body and exhaust gas purifying apparatus - Google Patents

Abstract

A honeycomb structured body and an exhaust gas purifying apparatus are provided to improve resistance against pressure applied to an outer surface of the honeycomb structured body. A honeycomb structured body(10) comprises a cylindrical honeycomb structured block including honeycomb structured units(20,200) in which a plurality of cells are arranged in parallel with each other with a cell wall interposed between cells. The honeycomb structured block has an outer surface where a sealing layer(11) is formed. The honeycomb structured body and the honeycomb structured block have outer surfaces with convex-concaves. The honeycomb structured unit includes inorganic particles, inorganic fiber and/or whisker. Formula 0.3mm<=M1 is satisfied, wherein M1=D1-D2, wherein D1 is the distance between the center(c1) of the least square curve obtained by a least square method and a concentric least circumscribed curve having the center(c1) of the least square curve, and D2 is the distance between the center of the least square curved and a concentric maximum circumscribed curve having the center of the least square curve. Formula 0.5mm<=M2<=7.0mm is satisfied, wherein M2=D3-D4, wherein D3 is the distance between the center(c2) of the least square curve obtained by a least square method and a concentric least circumscribed curve having the center(c2) of the least square curve, and D4 is the distance between the center of the least square curved and a concentric maximum circumscribed curve having the center of the least square curve.

Description

Honeycomb Structured Body and Exhaust Gas Purifying Apparatus}

1 is a perspective view schematically showing an example of the honeycomb structural body of the present invention.

2 (a) to 2 (c) are perspective views schematically showing an example of a honeycomb unit constituting the honeycomb structural body of the present invention.

3 is a perspective view schematically showing another example of the honeycomb structural body of the present invention.

Fig. 4A is a diagram showing an example of a curve drawn by plotting position data of a point on a contour of a cross section of the honeycomb block on a two-dimensional coordinate axis.

Fig. 4 (b) shows the least-squares curve drawn by the least square method using the position data shown in Fig. 4 (a), and the circularity when the circularity is obtained according to JIS B 0621. It is a figure which shows an example of two circles which generate the minimum area | region.

Fig. 5A is a front view schematically showing another example of the aggregate honeycomb structured body in the honeycomb structured body of the present invention.

5B is a front view schematically showing another example of the integrated honeycomb structured body.

Fig. 6A is a perspective view schematically showing another example of the honeycomb structural body of the present invention.

FIG. 6B is a perspective view schematically showing a cross-sectional curve drawn by a cross section perpendicular to the longitudinal direction of the honeycomb block in A, B, and C of the honeycomb structural body shown in FIG. 6A.

It is sectional drawing which shows typically an example of the exhaust gas purification apparatus of this invention.

FIG. 8A is a perspective view schematically showing an example of a honeycomb structured body in which a mat-like holding and sealing material is wound in the exhaust gas purifying apparatus shown in FIG. 7.

FIG. 8B is a partially enlarged cross-sectional view of FIG. 8A.

9 is an electron microscope (SEM) photograph of the cell wall of the honeycomb unit according to Example 1. FIG.

<Explanation of symbols for the main parts of the drawings>

10, 30, 50, 60, 500: honeycomb structure

11, 61: sealing material layer (adhesive layer)

20, 200, 210, 65: honeycomb unit

21, 31, 201, 211: through holes

22, 32, 202, 212: cell wall

[Patent Document 1] Japanese Patent Application Laid-Open No. 10-263416

[Patent Document 2] Japanese Patent Application Laid-Open No. 5-213681

[Patent Document 3] DE4341159

[Patent Document 4] Japanese Patent Application Laid-Open No. 2003-262118

[Patent Document 5] Japanese Patent Application Laid-Open No. 2001-329836

[Patent Document 6] Japanese Unexamined Patent Publication No. 2003-260322

The present invention relates to a honeycomb structural body and an exhaust gas purification apparatus.

Conventionally, honeycomb catalysts generally used in automobile exhaust gas purification are integrally supported by supporting high specific surface area materials such as activated alumina and catalytic metals such as platinum on the surface of cordierite-like honeycomb structures having low thermal expansion properties. Is being manufactured. In addition, alkaline earth metals such as Ba are supported as the NOx storage agent for the treatment of NOx in an excess oxygen atmosphere such as a lean burn engine and a diesel engine.

By the way, in order to further improve the purification performance, it is necessary to increase the contact probability of the exhaust gas with the catalyst noble metal and the NOx sorbent. For this purpose, it is necessary to make the carrier more specific surface area, to reduce the particle size of the noble metal and to make it highly dispersed. However, simply increasing the supporting amount of a high specific surface area material such as activated alumina only leads to an increase in the thickness of the alumina layer, and does not lead to an increase in the probability of contact, or a disadvantage such as an excessively high pressure loss. Cell shapes, cell densities, wall thicknesses, and the like have been studied (see, for example, Japanese Patent Application Laid-Open No. Hei 10-263416).

On the other hand, as a honeycomb structural body containing a high specific surface area material, a honeycomb structural body extruded together with an inorganic fiber and an inorganic binder is known (see, for example, Japanese Patent Application Laid-Open No. H5-213681). In addition, for the purpose of increasing the size of such a honeycomb structured body, it is known to join a honeycomb unit through an adhesive layer (see, for example, DE4341159).

However, high specific surface area materials, such as alumina, sintering progresses by heat aging, and the specific surface area falls, and supported catalyst metals, such as platinum, aggregate accordingly, and a particle size is large and a specific surface area becomes small. In other words, in order to have a higher specific surface area after thermal aging, it is necessary to increase the specific surface area at an early stage. As described above, in order to further improve the purification performance, it is necessary to increase the contact probability of the exhaust gas, the catalyst noble metal and the NOx sorbent. That is, it is important to make the carrier more specific surface area, to make the particles of the catalyst metal smaller and to be more dispersed, and to activate the activated alumina on the surface of the cordierite-like honeycomb structure such as Japanese Patent Application Laid-Open No. Hei 10-263416. In the case of supporting a high specific surface area material such as platinum and a catalytic metal such as platinum, the catalyst carrier was high specific surface area by studying the cell shape, the cell density and the wall thickness in order to increase the contact probability with the exhaust gas. As a result, the catalytic metal was not sufficiently dispersed, so that the purification performance of the exhaust gas after heat aging was insufficient.

In addition, the said heat aging means both the heat aging resulting from the heat at the time of using as a catalyst carrier, the heat aging at the time of an accelerated test by heat, etc.,.

Therefore, in order to make up for the deficiency, it has been attempted to solve the problem by supporting a large amount of the catalyst metal or increasing the size of the catalyst carrier itself. However, precious metals such as platinum are very expensive and are a limited precious resource. In addition, when installing in an automobile, since the installation space is very limited, nothing could be said to be a suitable means.

In addition, the honeycomb structural body of JP-A-5-213681, which extrudes a high specific surface area material together with an inorganic fiber and an inorganic binder, has a high specific surface area and is sufficient as a carrier because the substrate itself is made of a high specific surface area material. The catalyst metal can be highly dispersed, but the alumina of the substrate cannot be sufficiently sintered in order to maintain the specific surface area, and the strength of the substrate is very weak.

In addition, when used for automobiles as described above, the space for installation is very limited. Therefore, in order to increase the specific surface area of the carrier per unit volume, a means such as thinning of the cell wall is used, but the strength of the substrate is further weakened by doing so. In addition, alumina and the like have a large coefficient of thermal expansion, and cracks easily occur due to thermal stress during firing (preliminary firing) and during use. In consideration of these, when used for automobiles, external stresses such as thermal stress or large vibration due to rapid temperature change are applied at the time of use, so that they are easily broken and cannot maintain their shape as a honeycomb structure, and also cannot function as a catalyst carrier. There was a problem.

In addition, the catalyst support for automobiles in DE4341159 discloses that the honeycomb structure has a cross-sectional area of 200 cm ² or more because the honeycomb structure is intended to be enlarged. When used in a situation in which a large vibration or the like is applied, there is a problem in that it is easily broken as described above, the shape cannot be maintained, and the catalyst carrier cannot function.

In the exhaust gas purifying apparatus, the honeycomb structured body is installed in a casing connected to the exhaust passage of the internal combustion engine through the mat-shaped holding seal, and the exhaust gas discharged from the internal combustion engine passes through the honeycomb structured body.

However, in the exhaust gas purifying apparatus having the above-described configuration, in the honeycomb structured body provided in the casing via the mat-shaped holding sealant, a sealant layer is usually formed on the outer circumferential surface thereof, and the cross-sectional shape perpendicular to the longitudinal direction is approximately It was close to the circle. Therefore, when the inflow amount of the exhaust gas increases, the pressure applied to the end surface of the exhaust gas inflow side of the honeycomb structural body becomes high, or the casing is heated to a high temperature to expand more than the honeycomb structural body, thereby causing the mat-like holding seal in the casing. When the fixing force of a honeycomb structural body fell, the position shift of the honeycomb structural body may generate | occur | produce in a casing.

When the positional shift of the honeycomb structural body occurs in the casing as described above, the longitudinal direction of the honeycomb structural body and the flow direction of the exhaust gas are non-parallel, and the honeycomb structural body and the casing may come into contact with each other to cause cracks in the honeycomb structural body. In addition, the mat-shaped holding seal member hangs on the exhaust gas inflow side end face of the honeycomb structured body, blocking the cell exposed to the exhaust gas inflow side end surface of the honeycomb structured body, and the purification efficiency of exhaust gas may fall.

Therefore, in order to prevent misalignment of the honeycomb structured body in the casing, when disposing the honeycomb structured body in the casing through the mat-like holding seal member, the casing is applied to the outer circumferential portion of the honeycomb structural body with considerable pressure. You can also consider how to install it. However, in such a method, cracks may occur in the honeycomb structured body due to the pressure of the mat-like holding sealing material, or work may be difficult, resulting in low productivity and economic disadvantage.

On the other hand, the honeycomb structural body which improves the holding force of a honeycomb structural body by adjusting roundness by making a cross-sectional shape into a flat state from a circle | round | yen (for example, refer Unexamined-Japanese-Patent No. 2003-262118) is disclosed. Moreover, the honeycomb structural body which adjusted the roundness by forming an unevenness | corrugation in the outer peripheral part is disclosed (for example, refer Unexamined-Japanese-Patent No. 2001-329836). In these honeycomb structures, when the mat-like holding seal material penetrates to fill the concave portion of the outer circumferential portion of the honeycomb structural body when installed in the casing through the mat-like holding sealing material as the exhaust gas purification device, the The fixing force in the casing was improved, the positional displacement of the honeycomb structural body hardly occurred in the casing, and the holding stability of the honeycomb structural body could be improved.

However, it has been found that in the honeycomb structure in which a sealing material layer (coating layer) is formed in the honeycomb block, even if the outer periphery is adjusted simply by forming an uneven layer on the outside, cracking may occur due to thermal stress during use even when the holding force is improved. .

On the other hand, the honeycomb structural body which raised the isotactic strength by setting the joining layer of the inclined part of a cell thick is disclosed (for example, refer Unexamined-Japanese-Patent No. 2003-260322).

However, the honeycomb structural body of JP-A-2003-260322 has no irregularities on the outer surface of the honeycomb structural body after forming the sealing material layer (coating layer). By the way, when there was no unevenness | corrugation, it turned out that a crack arises according to the thickness of a sealing material layer irrespective of a position.

The present invention has been made to solve such a problem, and is strong against thermal shock and vibration, has high strength, does not generate cracks even when thermal stress occurs, and easily cracks or breaks even when high pressure is applied from the outer circumferential surface thereof. It is an object of the present invention to provide a honeycomb structural body which is excellent in durability, and which can further disperse a catalyst component, and an exhaust gas purifying apparatus using the honeycomb structural body.

The honeycomb structural body of the present invention is a honeycomb structural body in which a sealing material layer (coating layer) is provided at an outer circumference of a columnar honeycomb block including a honeycomb unit in which a plurality of cells are arranged in a longitudinal direction with cell walls interposed therebetween,

Unevenness is formed on the outer circumferential surface of the honeycomb structure and the honeycomb block,

The honeycomb unit comprises inorganic particles, inorganic fibers and / or whiskers,

Based on the points constituting the contour of the cross section perpendicular to the longitudinal direction of the honeycomb structured body, the least square curve is obtained by the least square method, and its center is referred to as c1, and the concentric with the center c1 of the least square curve. The distance between the minimum circumscribed curve and the center c1 is called D1, and the distance between the concentric maximum inscribed curve having the center c1 of the least square curve and the center c1 is called D2, and defined as M1 = D1-D2, 0.3 mm ≦ M1,

Based on the points constituting the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block, the least square curve is obtained by the least square method, the center of which is referred to as c2, and the concentric with the center c2 of the least square curve. The distance between the minimum circumscribed curve and the center c2 is called D3, and the distance between the concentric maximum inscribed curve having the center c2 of the least square curve and the center c2 is called D4, and M2 = D3-D4, and 0.5 mm ≦ M2? 7.0 mm.

In the honeycomb structural body, the M1 is preferably 3.0 mm or less.

In addition, it is preferable that the center c1 and the center c2 do not coincide in the honeycomb structured body, and the distance between the center c1 and the center c2 is preferably 0.1 to 10.0 mm.

In the honeycomb structured body, when three or more points of the center c2 of the least square curve are obtained in the longitudinal direction of the honeycomb block, the center c2 does not exist on a straight line parallel to the length direction of the honeycomb block. Preferably, when at least three points of the center c1 of the least-squares curve are obtained in the longitudinal direction of the honeycomb structural body, it is preferable that the center c1 is not present on a straight line parallel to the longitudinal direction of the honeycomb structural body.

In the honeycomb structural body, the honeycomb block is preferably configured by binding a plurality of honeycomb units.

In this case, the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb unit is preferably 5 to 50 cm ² . Moreover, it is preferable that the sum total of the cross-sectional area in the cross section perpendicular | vertical to the longitudinal direction of the said honeycomb unit occupies 85% or more of the cross-sectional area in the cross section perpendicular | vertical to the longitudinal direction of the said honeycomb structural body.

In the honeycomb structural body, the inorganic particles are preferably one or more selected from the group consisting of alumina, silica, zirconia, titania, ceria, mullite and zeolite.

In the honeycomb structural body, the inorganic fibers and / or whiskers are preferably at least one member selected from the group consisting of alumina, silica, silicon carbide, silica alumina, glass, potassium titanate and aluminum borate.

In the honeycomb structure, the honeycomb unit is manufactured using a mixture comprising the inorganic particles and the inorganic fibers and / or whiskers and an inorganic binder,

The inorganic binder is preferably at least one member selected from the group consisting of alumina sol, silica sol, titania sol, water glass, sepiolite and attapulgite.

Preferably, the honeycomb structured body is supported by a catalyst, and the catalyst preferably includes one or more selected from the group consisting of noble metals, alkali metals, alkaline earth metals and oxides.

The exhaust gas purifying apparatus of the present invention is characterized in that the honeycomb structural body of the present invention is provided in a casing which is connected to an exhaust passage of an internal combustion engine via a mat-like holding seal. In the exhaust gas purifying apparatus, the mat-like holding and sealing material is preferably an unexpanded ceramic fibrous mat.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, the honeycomb structural body and exhaust gas purification apparatus of this invention are demonstrated, referring drawings.

First, the honeycomb structural body of the present invention will be described.

The honeycomb structural body of the present invention is a honeycomb structural body in which a sealing material layer (coating layer) is provided at an outer circumference of a columnar honeycomb block including a honeycomb unit in which a plurality of cells are arranged in a longitudinal direction with cell walls interposed therebetween,

Unevenness is formed on the outer circumferential surface of the honeycomb structure and the honeycomb block,

The honeycomb unit comprises inorganic particles, inorganic fibers and / or whiskers,

Based on the points constituting the contour of the cross section perpendicular to the longitudinal direction of the honeycomb structured body, the least square curve is obtained by the least square method, and its center is referred to as c1, and the concentric with the center c1 of the least square curve. The distance between the minimum circumscribed curve and the center c1 is called D1, and the distance between the concentric maximum inscribed curve having the center c1 of the least square curve and the center c1 is called D2, and defined as M1 = D1-D2, 0.3 mm ≦ M1,

Based on the points constituting the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block, the least square curve is obtained by the least square method, the center of which is referred to as c2, and the concentric with the center c2 of the least square curve. The distance between the minimum circumscribed curve and the center c2 is called D3, and the distance between the concentric maximum inscribed curve having the center c2 of the least square curve and the center c2 is called D4, and M2 = D3-D4, and 0.5 mm ≦ M2? 7.0 mm.

The honeycomb structural body of the present invention is composed of a columnar honeycomb block including a honeycomb unit in which a plurality of cells are arranged in a longitudinal direction with cell walls interposed therebetween, but the honeycomb block has a plurality of cells interposed between the cell walls. The columnar honeycomb unit arranged in the longitudinal direction at the side may be configured by binding through a sealant layer (adhesive layer) (hereinafter, a honeycomb structured body including a honeycomb block of the structure) The structure (also referred to as a block) may be composed of a ceramic member which is entirely sintered as a whole (hereinafter, a honeycomb structure (block) including a honeycomb block of the above structure is also referred to as an integrated honeycomb structure (block)). .

In the honeycomb structural body of the present invention, in the case where the honeycomb block is the aggregate honeycomb block, the cell wall includes a cell wall that sandwiches the cells of the honeycomb unit, and an encapsulant layer between the outer wall of the honeycomb unit and the honeycomb unit (preferably). It also functions as an adhesive), and on the other hand, when the honeycomb block is the integrated honeycomb block, it is composed of only one cell wall.

1 is a perspective view schematically showing an example of an aggregate type honeycomb block used in the honeycomb structured body of the present invention, and FIGS. 2 (a) to 2 (c) are honeycomb types that constitute the honeycomb block shown in FIG. It is a perspective view which shows an example of a unit typically.

As shown in FIG. 1, in the honeycomb structure 10 of the present invention, the honeycomb units 20, 200, 210 made of a plurality of porous ceramics having different shapes are bound to each other through the sealant layer 11 to form an approximate structure. Although it forms the cylindrical honeycomb block and is not shown in FIG. 1, the unevenness | corrugation is formed in the outer peripheral surface of the said honeycomb block.

The honeycomb unit 20 constituting such a honeycomb structural body 10 has a cross section in which a plurality of cells 21 are arranged side by side with the cell wall 22 in the longitudinal direction thereof, as shown in FIG. It is an approximate square prismatic view from.

In addition, in the honeycomb unit 200, as shown in FIG. 2B, a plurality of cells 201 are arranged in parallel in the longitudinal direction with the cell wall 202 interposed therebetween, and a part of the outer peripheral part thereof is cut off and removed. It is a substantially fan-shaped columnar shape seen from the cross section, and a part of cell 201 is exposed in the cut-out part of the said outer peripheral part. That is, groove-shaped irregularities are formed in a portion of the outer circumferential surface of the honeycomb unit 200 by the exposed cells 201.

In addition, in the honeycomb unit 210, as shown in FIG. 2C, a plurality of cells 211 are arranged in parallel in the longitudinal direction with the cell walls 212 interposed therebetween, and the vicinity of each corner of one of the outer peripheral parts thereof is cut off. The columnar shape is removed and a part of the cell 211 is exposed to the cut-out portion of the outer peripheral portion. That is, groove-shaped unevenness is formed in a part of the outer peripheral surface of the honeycomb unit 210 by the exposed cells 211.

By combining the honeycomb units 20, 200, and 210 having the above-described structure through the sealing material layer 11, the honeycomb block 10 of the honeycomb structure is constructed, and a prismatic honeycomb unit having no irregularities on its outer circumferential surface is formed. 20 is located near the center of the honeycomb block, and the honeycomb unit 200 and the honeycomb unit 210 having groove-shaped irregularities on the outer circumferential surfaces thereof are located near the outer circumference of the honeycomb block.

That is, in the honeycomb structural body 10, the groove-shaped unevenness formed on the outer circumferential surface of the honeycomb block is a part of the cells constituting the honeycomb unit 200 and the honeycomb unit 210, and the remaining portion is the outer circumferential surface. Has been exposed.

3 is a perspective view schematically showing an example of an integrated honeycomb block used in the honeycomb structural body of the present invention.

This honeycomb block constitutes an approximately cylindrical honeycomb block composed of one honeycomb unit arranged in the longitudinal direction with a plurality of cells 31 interposed therebetween, and the outer peripheral surface of the honeycomb block. Unevenness 33 is formed in this.

In the honeycomb structured structure 30 having such a structure, the unevenness 33 formed on the outer circumferential surface of the honeycomb block is a cell constituting the honeycomb block as in the case of the honeycomb structure 10 shown in Figs. Part of (31) is deleted and the remaining part is exposed on the outer circumferential surface.

As described above, in the honeycomb structural body of the present invention, unevenness is formed on the outer circumferential surface of the honeycomb block in either of the collective honeycomb structural body or the integrated honeycomb structural body.

According to the researches of the present inventors, in the past, such a honeycomb structural body has been flattened by providing a sealant layer to uniform the entire outer circumferential part and removing groove-shaped irregularities on the side of the cylinder. However, when a thermal shock test or the like of the honeycomb structural body is performed In the case of leaving unevenness (preferably unevenness on the groove so as to have an effect on all cross-sections in the longitudinal direction) on the outer circumferential surface of the mold structure, it has been found that thermal shock resistance deteriorates when the unevenness of the honeycomb block is unbalanced. . Although the reason is not clear, it is considered as follows.

That is, in the honeycomb structured body, heat is emitted evenly from the center toward the outer circumferential portion. If there is irregularities on the surface, the surface area of the surface is improved, which results in a cooling effect and is likely to cause a sudden temperature shock. In addition, when viewed microscopically, it is considered that the apex of the convex portion is more susceptible to thermal shock than the bottom portion of the concave portion.

In this case, since the honeycomb unit and the sealing material layer (coating layer) do not exhibit completely the same physical properties due to different materials or different densities, etc., it is considered that heat stress also occurs in the portion.

By changing the unevenness of the two parts described above, it is believed that the internal distortion caused by each thermal stress can be alleviated.

EMBODIMENT OF THE INVENTION Hereinafter, the unevenness | corrugation formed in the outer peripheral surface of the honeycomb structural body and honeycomb block of this invention is demonstrated.

In the honeycomb structural body, the same measurement may be performed after the sealing material layer (coating layer) is formed on the honeycomb block, and therefore, the description is limited to the measurement of the honeycomb block. Of course, the measurement of the honeycomb block may be performed during the manufacturing process of the honeycomb structured body. However, after manufacturing, the same measurement may be performed on the honeycomb block portion after removing the sealing material layer (coating layer) by processing or polishing.

In the honeycomb block used for the honeycomb structural body of the present invention, in order to obtain the size of the unevenness formed on the outer circumferential surface of the honeycomb block, first, a cross section perpendicular to the longitudinal direction of the honeycomb block (hereinafter, simply referred to as a honeycomb block) The position data of the point on the outline obtained by measuring ten or more points on the outline of the outline) is plotted on two-dimensional coordinates.

Fig. 4A is a diagram showing an example of a curve drawn by plotting position data of a point on a contour of a cross section of the honeycomb block on a two-dimensional coordinate axis.

As shown in Fig. 4A, when the position data measured for the point on the contour is plotted on a two-dimensional coordinate axis, a curve 40 having a bent portion having a shape substantially the same as the cross section of the honeycomb block is obtained. Painted.

In addition, the curve 40 shown to FIG. 4 (a) is a figure which plotted the position data with respect to the point on the outline of the cross section of the honeycomb block of the honeycomb structure 10 shown in FIG. 1 on the two-dimensional coordinate axis. , Two-dimensional coordinate axis is omitted.

In the honeycomb structural body of the present invention, the position data for the point on the contour is measured at least 10 places. If the number of position data to be measured is less than 10, the shape of the curve drawn on the two-dimensional coordinate axis is greatly different from the cross-sectional shape of the honeycomb block so that the distribution of irregularities formed on the outer circumferential surface of the honeycomb block cannot be accurately obtained. do.

The number of position data to be measured is not particularly limited as long as it is 10 or more, but is preferably 100 or more. This is because the shape of the curve drawn on the two-dimensional coordinate axis is closer to the cross-sectional shape of the actual honeycomb block.

Further, the points on the contour to be measured are preferably equally spaced on the contour. This is because the uneven distribution of the outer circumferential surface of the honeycomb block can be measured more accurately.

When plotting the position data of the point on the contour on a two-dimensional coordinate axis, a commercially available three-dimensional measuring instrument can be used.

It does not specifically limit as said three-dimensional measuring machine, For example, "LEGEX series", "FALCIO-APEX series", "Bright-Apex series", "MACH series", "CHN series", "BH-V" by Mitsutoyo Corporation Series ”and the like.

Subsequently, a least-squares curve is drawn on the two-dimensional coordinate axis by the least-squares method using the positional data on the point on the contour to find the center c2.

Subsequently, a concentric minimum circumscribed curve having the center c2 of the least-squares curve and a concentric maximum inscribed curve having the center c2 of the least-squares curve are obtained.

The concentric minimum circumscribed curve and the concentric maximum circumscribed curve are not limited to circles, and may be ellipses or other curves. In addition, the concentric minimum circumscribed curve and the concentric maximum circumscribed curve become phase-like forms that share the center c2.

In addition, as long as it is a circle, it should follow the method of obtaining roundness of JIS B 0621.

4 (b) is a diagram showing an example of a least square curve drawn by the least square method using the position data shown in FIG. 4 (a), a concentric minimum circumscribed curve, a concentric maximum inscribed curve, and a center c2; , Two-dimensional coordinate axis is omitted.

As shown in Fig. 4 (b), the least-squares curve 41 has smoother concavities and convexities than the curve 40 shown in Fig. 4 (a), and has a larger distance from the center c2. And a concentric maximum inscribed curve 43 of a smaller distance.

Here, the concentric minimum circumscribed curve 42 and the concentric maximum circumscribed curve 43 are concentric curves as seen from the center c2 as described above, and specifically, the concentric minimum circumscribed curve 42 is a least square curve 41 on the line. At least a portion of the convex portion of), and the other portion of the least squares curve 41 is the curve having a minimum distance from the center c2 existing inside the concentric least circumscribed curve, and the concentric maximum inscribed curve 43 is At least some of the concave portions of the least-squares curve 41 exist on the line, and the curve having a maximum distance from the center c2 where other portions of the least-squares curve 41 exist outside the concentric maximal inscribed curve. to be.

In the present invention, the distance D3 between the concentric minimum circumscribed curve of the least-squares curve and the center c2 (see Fig. A) and the distance D4 between the concentric maximum inscribed curve of the least-squares curve and the center c2 (see Fig. B) ) And calculate D3-D4 = M2.

In the honeycomb block of the honeycomb structural body of the present invention, the size of the irregularities formed on the outer surface of the honeycomb block described above by M2 can be represented.

In addition, in the present invention, the honeycomb structural body is obtained in the same manner as the center of the honeycomb structural body, and the minimum squared curve is calculated by the least square method based on the point that forms the contour of the cross section perpendicular to the longitudinal direction of the honeycomb structural body. do. Further, a concentric minimum circumscribed curve having the center c1 of the least-squares curve is obtained, and the distance between the concentric minimum circumscribed curve and the center c1 is D1. Further, a concentric maximum inscribed curve having the center c1 of the least-squares curve is obtained, and D1-D2 = M1 is calculated while the distance between the concentric maximum inscribed curve and the center c1 is D2.

In the honeycomb structural body of the present invention, M1 is 0.3 mm or more.

If M1 is less than 0.3 mm, almost no irregularities are formed on the outer circumferential surface of the honeycomb structured body, and such honeycomb structured body does not cause the problem of thermal stress as described above.

It is preferable that M1 is 3.0 mm or less. When M1 exceeds 3.0 mm, irregularities formed on the outer circumferential surface of the honeycomb structural body are large, and such honeycomb structural body is likely to cause cracks or defects due to thermal stress on the convex portions of the outer circumferential surface of the honeycomb block as described above. Lose.

In the honeycomb block in which the honeycomb structural body of the present invention is used, 0.5 mm ≦ M2 ≦ 7.0 mm.

If M2 is less than 0.5 mm, almost no irregularities are formed on the outer circumferential surface of the honeycomb block, and it is considered that thermal stress is generated between the honeycomb block and the sealing material layer (coating layer) to cause cracking.

On the other hand, when M2 exceeds 7.0 mm, the unevenness | corrugation formed in the outer peripheral surface of the said honeycomb block is large, and such a honeycomb structural body is considered that the thermal stress arises between a honeycomb block and a sealing material layer (coating layer), and a crack arises.

Thus, in the honeycomb structural body of the present invention, irregularities of a predetermined size are formed on the outer circumferential surface of the honeycomb block. The unevenness formed on the outer circumferential surface of the honeycomb block may be a part of the cells constituting the honeycomb block, such as the honeycomb structure shown in Figs. 1 to 3, and the remaining portion may be exposed on the outer circumferential surface, for example, FIG. Stepped irregularities may be formed on the outer circumferential surface of the honeycomb block, such as the honeycomb structural body 50 and the honeycomb structural body 500 shown in (a) and 5 (b).

5A is a front view schematically showing another example of the aggregate honeycomb block 50, and FIG. 5B is a front view schematically showing another example of the integrated honeycomb block 500. FIG. .

The honeycomb block 50 and the honeycomb block 500 shown in FIGS. 5 (a) and 5 (b) have a substantially square cross-sectional shape of all cells including cells formed near the outer circumferential surface of the honeycomb block. The unevenness formed on the outer circumferential surface of the honeycomb block is stepped in accordance with the cross-sectional shape of the cell near the outer circumferential surface of the honeycomb block.

These honeycomb blocks 50 and 500 are approximately the same as the honeycomb structure 10 shown in FIG. 1 and the honeycomb structure 30 shown in FIG. 3 except that the shapes of the irregularities formed on the outer circumferential surface of the honeycomb block are different. Has the same structure.

The honeycomb unit constituting the honeycomb structural body of the present invention comprises inorganic particles, inorganic fibers and / or whiskers.

As the inorganic particles, particles containing alumina, silica, zirconia, titania, ceria, mullite, zeolite and the like are preferable. These may be used independently and may use 2 or more types together. Among these, particles containing alumina are particularly preferred.

As the inorganic fiber or whisker, inorganic fibers or whiskers containing alumina, silica, silicon carbide, silica alumina, glass, potassium titanate, aluminum borate and the like are preferable. These may be used independently and may use 2 or more types together.

As for the preferable aspect ratio (length / diameter) of the said inorganic fiber or whisker, a preferable lower limit is 2, a more preferable lower limit is 5, and a more preferable lower limit is 10. On the other hand, a preferable upper limit is 1000, a more preferable upper limit is 800, and a more preferable upper limit is 500.

The lower limit with respect to the quantity of the said inorganic particle contained in the said honeycomb unit is 30 weight%, a more preferable lower limit is 40 weight%, and a further preferable lower limit is 50 weight%.

On the other hand, a preferable upper limit is 97 weight%, a more preferable upper limit is 90 weight%, a more preferable upper limit is 80 weight%, and an especially preferable upper limit is 75 weight%.

When the content of the inorganic particles is less than 30% by weight, the amount of the inorganic particles that contributes to the improvement of the specific surface area is relatively small, so that the specific surface area of the honeycomb structure is small, and the catalyst component can be highly dispersed when supporting the catalyst component. There may be no. On the other hand, when it exceeds 97 weight%, since the quantity of the inorganic fiber and / or whisker which contributes to strength improvement becomes comparatively small, the intensity | strength of a honeycomb structural body will fall.

The lower limit with respect to the total amount of the inorganic fibers and / or whiskers contained in the honeycomb unit is preferably 3% by weight, more preferably 5% by weight, and still more preferably 8% by weight. On the other hand, a preferable upper limit is 70 weight%, a more preferable upper limit is 50 weight%, a more preferable upper limit is 40 weight%, and an especially preferable upper limit is 30 weight%.

If the total amount of the inorganic fibers and / or whiskers is less than 3% by weight, the strength of the honeycomb structural body decreases, and if the total amount of the inorganic fibers and / or whiskers exceeds 50%, the amount of the inorganic particles contributing to the improvement of the specific surface area is relatively small. As a specific surface area, the catalyst component may not be highly dispersed when the catalyst component is supported.

The honeycomb unit is also preferably manufactured using a mixture comprising the inorganic particles and the inorganic fibers and / or whiskers and inorganic binders.

Thus, by using the mixture containing an inorganic binder, the honeycomb unit of sufficient strength can be obtained even if the temperature which bakes the produced | generated body is reduced.

An inorganic sol, a clay-based binder, etc. can be used as said inorganic binder, As a specific example of the said inorganic sol, an alumina sol, a silica sol, a titania sol, water glass, etc. are mentioned, for example. Moreover, as a clay type | system | group binder, double-chain structured clays, such as clay, kaolin, montmorillonite, sepiolite, and attapulgite, etc. are mentioned, for example.

Among these, one or more selected from the group consisting of alumina sol, silica sol, titania sol, water glass, sepiolite and attapulgite is preferable.

As for solid content of the raw material paste adjusted in the manufacturing process mentioned later, the quantity of the said inorganic binder has a preferable lower limit of 5 weight%, a more preferable lower limit of 10 weight%, and a further preferable lower limit of 15 weight%. On the other hand, a preferable upper limit is 50 weight%, a more preferable upper limit is 40 weight%, and a further more preferable upper limit is 35 weight%.

If the content of the inorganic binder exceeds 50% by weight, moldability becomes poor.

In addition, when the honeycomb structural body of the present invention is the aggregate honeycomb structural body shown in Fig. 1, the plurality of honeycomb units are bound through a sealing material layer that functions as an adhesive, and the material constituting the sealing material layer (adhesive layer). It does not specifically limit as a thing, For example, what contains an inorganic binder, inorganic fiber, and / or inorganic particle, etc. are mentioned. Moreover, if necessary, the thing with which the organic binder was mix | blended can also be used.

In addition, as mentioned above, the material which comprises the sealing material layer (coating layer) of the outer peripheral surface of the honeycomb block of the honeycomb structural body of this invention may consist of the same material as the said sealing material layer (adhesive layer), and consists of another material It may be. In addition, when the said sealing material layer (adhesive layer) and a sealing material layer (coating layer) consist of the same material, the compounding ratio of the material may be the same and may differ.

As said inorganic binder, a silica sol, an alumina sol, etc. are mentioned, for example. These may be used independently and may use 2 or more types together. Among the inorganic binders, silica sol is preferable.

As said organic binder, polyvinyl alcohol, methyl cellulose, ethyl cellulose, carboxymethyl cellulose etc. are mentioned, for example. These may be used independently and may use 2 or more types together. Among the organic binders, carboxymethyl cellulose is preferred.

Examples of the inorganic fibers include ceramic fibers such as silica-alumina, mullite, alumina, silica, and the like. These may be used independently and may use 2 or more types together. Among the inorganic fibers, alumina fibers and silica-alumina fibers are preferable. The lower limit of the fiber length of the inorganic fiber is preferably 5 µm. Moreover, 100 mm is preferable and, as for the upper limit of the fiber length of the said inorganic fiber, 100 micrometers is more preferable. If it is less than 5 micrometers, the elasticity of a sealing material layer may not be improved, On the other hand, when it exceeds 100 mm, since inorganic fiber becomes easy to take a form like a hair ball, dispersion with an inorganic particle may become poor. Moreover, when it exceeds 100 micrometers, it may become difficult to make thickness of a sealing material layer thin.

Examples of the inorganic particles include carbides, nitrides, and the like, and specific examples thereof include inorganic powders containing silicon carbide, silicon nitride, boron nitride, and the like. These may be used independently and may use 2 or more types together. Among the inorganic particles, silicon carbide excellent in thermal conductivity is preferable.

In addition, when the honeycomb structural body of the present invention is a collective honeycomb structural body as described above, that is, when the honeycomb block is configured by binding a plurality of honeycomb units, it is perpendicular to the longitudinal direction of the honeycomb unit. As for the cross-sectional area in a cross section, a preferable lower limit is 5 cm <^2> , a more preferable lower limit is 6 cm <^2> , and a more preferable lower limit is 8 cm <^2> . On the other hand, a preferable upper limit is 50 cm <^2> , a more preferable upper limit is 40 cm <^2> , and a more preferable upper limit is 30 cm <^2> .

5 cm ² If less, the cross-sectional area of the sealing material layer joining the plurality of honeycomb units becomes larger, so that the specific surface area carrying the catalyst becomes relatively small, and the pressure loss may become relatively large.If the cross-sectional area exceeds 50 cm ² , the unit The magnitude | size of x may become so large that thermal stress which arises in each honeycomb unit cannot fully be suppressed.

On the other hand, if the cross-sectional area of a honeycomb unit is 5-50 cm <^2> , it becomes possible to adjust the ratio which the sealing material layer with respect to a honeycomb structure has. As a result, the specific surface area per unit volume of the honeycomb structural body can be largely maintained, the catalyst component can be highly dispersed, and the shape as the honeycomb structural body can be maintained even when external force such as thermal shock or vibration is applied. In addition, it is preferable that a cross-sectional area is 5 cm <^2> or more also from a point where pressure loss becomes small.

In the present specification, the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb unit is a honeycomb that serves as a basic unit constituting the honeycomb structure when the honeycomb structure includes a plurality of honeycomb units having different cross-sectional areas. Refers to the cross-sectional area in the cross section perpendicular to the longitudinal direction of the mold unit, and typically refers to the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb unit with the largest cross-sectional area.

In addition, in the collective honeycomb structured body, since a plurality of honeycomb units have a structure in which a plurality of honeycomb units are joined through a sealing material layer (adhesive layer), the strength against thermal shock and vibration can be further increased.

The reason is assumed that even when a temperature distribution occurs in the honeycomb structural body due to a sudden temperature change or the like, the temperature difference generated in each honeycomb unit can be suppressed small. Or it is guessed because thermal shock and a vibration can be alleviated by a sealing material layer. The sealing material layer also prevents cracks from spreading throughout the honeycomb structured body even when a crack occurs in the honeycomb unit due to thermal stress, and also serves as a frame of the honeycomb structured body, and maintains the shape as a honeycomb structured body. It is therefore believed that the function as a catalyst carrier will not be lost.

Moreover, it is preferable that the sum total of the cross-sectional area in the cross section perpendicular | vertical to the longitudinal direction of the said honeycomb unit occupies 85% or more of the cross-sectional area in the cross section perpendicular | vertical to the longitudinal direction of the said honeycomb structural body, and occupies 90% or more. More preferred.

This is because if the ratio is less than 85%, the proportion of the cross-sectional area of the sealing material layer becomes large and the total cross-sectional area of the honeycomb unit is reduced, so that the specific surface area carrying the catalyst is relatively small and the pressure loss is relatively large.

In addition, the pressure loss can be made smaller at 90% or more.

In the pores of the honeycomb structural body of the present invention, a catalyst capable of purifying CO, HC, NOx and the like in the exhaust gas may be supported.

By carrying such a catalyst, the honeycomb structural body of the present invention functions as a catalytic converter for purifying the CO, HC, NOx and the like contained in the exhaust gas.

It does not specifically limit as said catalyst, For example, noble metals, such as platinum, palladium, rhodium, an alkali metal, alkaline-earth metal, oxide, etc. are mentioned.

These may be used independently and may use 2 or more types together.

The catalyst containing the noble metal is a so-called three-way catalyst, and the honeycomb structural body of the present invention on which the three-way catalyst is supported functions in the same way as a conventionally known catalytic converter. Therefore, detailed description of the case where the honeycomb structural body of the present invention also functions as a catalytic converter is omitted.

However, the catalyst which can be supported on the honeycomb structural body of the present invention is not limited to the above noble metal, and any catalyst can be supported as long as the catalyst can purify CO, HC, NOx, and the like in the exhaust gas.

As described above, the honeycomb structural body of the present invention is resistant to thermal shock because the irregularities controlled to a predetermined size are formed on the outer circumferential surface of the honeycomb block. Even when high pressure is applied from the outer circumferential surface, the cracks do not easily crack or break, and the durability is excellent.

In addition, since the honeycomb unit constituting the honeycomb structured body comprises inorganic particles, inorganic fibers and / or whiskers, the specific surface area is improved by the inorganic particles, and the honeycomb is formed by the inorganic fibers and / or whiskers. The strength of the mold unit is improved.

Such a honeycomb structural body of the present invention can be suitably used for catalytic converters and the like.

In the honeycomb structural body of the present invention, it is preferable that the center c1 and the center c2 do not coincide. As described above, the honeycomb structured body is referred to as a center mismatched honeycomb structured body.

In the center mismatched honeycomb structure, when the center c2 of the least curved honeycomb structure, i.e., at least three points in the longitudinal direction of the honeycomb block is obtained, the center c2 is the honeycomb block. When the center c1 does not exist on a straight line parallel to the longitudinal direction of or is obtained at least three points in the longitudinal direction of the honeycomb structure, the center c1 is the longitudinal direction of the honeycomb structure. It becomes easy to manufacture the honeycomb structural body which does not exist on the straight line parallel to the.

Further, in the case where the center mismatched honeycomb structured body is used as the exhaust gas purifying apparatus, the maintenance durability increases. Although this mechanism is not clear, in the case of heat transfer from the central portion of the filter to the peripheral portion in the center mismatched honeycomb structure, a portion where the heat transfer is good and a portion bad occurs. Therefore, the holding mat of the portion with high heat transfer generates fatigue, corrosion, crystallization, etc. due to heat, so that the holding force is poor, while the holding mat is relatively maintained. Therefore, it is considered that the compressive force is applied to the portion subjected to the thermal fatigue and the reduction of the push-out load is prevented.

In addition, the distance of c1-c2 is preferably 0.1 to 10.0 mm. The push-out strength does not increase because it is concentric below 0.1 mm. On the other hand, when the distance of c1-c2 exceeds 10.0 mm, since the temperature distribution becomes reversed, the holding force is reversed.

FIG. 6 (a) is a perspective view schematically showing an example of a honeycomb block used in the micro-curved honeycomb structure, and FIG. 6 (b) is A, B, and C of the honeycomb structure shown in FIG. 6 (a). Fig. 1 is a perspective view schematically showing a cross-sectional curve drawn by a contour of a cross section perpendicular to the longitudinal direction of the honeycomb block in Figs.

As shown in Fig. 6 (a), the micro-curved honeycomb structural body 60 has a sealing material layer (adhesive layer) 61 in which a honeycomb unit 65 in which a plurality of cells are arranged in a longitudinal direction with cell walls interposed therebetween. It consists of a honeycomb block on the column bound through a plurality. That is, the minute curved honeycomb structural body 60 has a structure substantially the same as that of the honeycomb structural body 10 shown in FIG. 1, and is an aggregate honeycomb structural body.

In the minute curved honeycomb structural body, irregularities are formed on the outer circumferential surface of the honeycomb block.

The unevenness formed on the outer circumferential surface of the honeycomb block is, as described with reference to FIGS. 2 (a) to 2 (c), 5 (a) and 5 (b), in the honeycomb structured body of the present invention. A part of the cells constituting the block may be deleted and the remaining part may be exposed on the outer circumferential surface, or may be formed in a step shape.

Moreover, it is preferable that the magnitude | size of the unevenness | corrugation formed in the outer peripheral surface of the said honeycomb block is controlled to become the same as the honeycomb structural body of this invention. This is because the isostatic strength of the honeycomb structure becomes excellent.

In the micro-curved honeycomb structure, as described above, when the center c2 of the least square curve (hereinafter also referred to as cross-sectional curve) of the honeycomb block is determined at least three points in the longitudinal direction of the honeycomb block, the center c2 is the above-mentioned. When the center c1 of the honeycomb structure that does not exist on a straight line parallel to the length direction of the honeycomb block or the center c1 of the least square curve of the honeycomb structure is obtained at least three points in the longitudinal direction of the honeycomb structure, the center c1 is the above. It is a honeycomb structure which does not exist on the straight line parallel to the longitudinal direction of a honeycomb structure.

That is, as shown in Fig. 6 (b), the minimum square curve obtained by the least square method based on the point constituting the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block of the honeycomb structural body 60. Centers c2-1, c2-2 and c2-3 are not on a straight line L parallel to the longitudinal direction of the honeycomb block.

According to the study of the inventors, the extrusion strength of the honeycomb structure is largely related to the center position of the cross-sectional curve drawn by the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block of the honeycomb structure, and the extrusion strength of the honeycomb structure Has been found to be excellent when the center c2 of one cross-sectional curve in the honeycomb block and the center c2 of the other cross-sectional curve are distributed within a predetermined range with respect to a straight line parallel to the longitudinal direction of the honeycomb block. .

Here, the "extrusion strength of the honeycomb structural body" means that the honeycomb structural body in a state of being fixed by holding the entire outer circumferential surface of the honeycomb block with a predetermined member withstands against external force such as pressure exerted from one end face thereof. The limit strength that can be said.

Although the reason is not clear, it is considered as follows.

That is, in the honeycomb structured body in which the entire outer circumferential surface of the honeycomb structured body is fixed by a predetermined member and is fixed, the stress caused by the external force is applied to the honeycomb block when an external force such as pressure is applied to one end surface thereof. Occurs from one cross-section toward the other cross-section.

At this time, if the center of one cross-sectional curve in the honeycomb block and the center of the other cross-sectional curve exist on a straight line parallel to the longitudinal direction of the honeycomb block, the stress generated in the honeycomb block is the honeycomb block Since it is transmitted linearly from one end face toward the other end face, the force acting between the honeycomb structural body and the member fixing the honeycomb structural body becomes large, and as a result, the extrusion strength of the honeycomb structural body is considered to be low.

On the other hand, if the center c2 of one cross-sectional curve and the center c2 of the other cross-sectional curve in the honeycomb block do not exist on a straight line parallel to the longitudinal direction of the honeycomb block, the stress generated in the honeycomb block is honeycomb-like. When transmitted from one end face to the other end face of the block, it is dispersed, and the force acting between the honeycomb structure and the member holding the honeycomb structure becomes small, and as a result, the extrusion strength of the honeycomb structure is considered to be high.

In order to increase the extrusion strength of the finely curved honeycomb structural body as described above, it is necessary to control the distribution of the center of the cross-sectional curve perpendicular to the longitudinal direction of the honeycomb block within a predetermined range.

Hereinafter, the distribution of the center of the said cross-sectional curve is explained in detail using the honeycomb structural body 60 etc. which were shown to FIG. 6 (a) and 6 (b).

That is, in order to obtain the distribution of the center c2 of the cross-sectional curve perpendicular to the longitudinal direction of the honeycomb block in the micro-curved honeycomb structural body, the center c2-1 at the cross-sectional curve A of the micro-curved honeycomb structural body 60 is first obtained. The positional data of, the positional data of the center c2-2 in the cross-sectional curve B, and the positional data of the center c2-3 in the cross-sectional curve C are obtained, respectively, and the positions of the centers c2-1, c2-2 and c2-3, respectively. Draw a least-squares straight line not shown from the data.

It does not specifically limit as a method of obtaining the position data of the center c2 of the said cross-sectional curve, For example, it can measure by the above-mentioned three-dimensional measuring instrument.

The number of position data of the center c2 of the cross section curve to be obtained is not particularly limited as long as it is three or more. If the data of the center c2 of the cross-sectional curve to be measured is less than three, it is because it is impossible to draw a least square line representing the image-like center of the cross-sectional curve perpendicular to the longitudinal direction of the honeycomb block.

The position data of the image-like center of the cross-sectional curve to be measured is not particularly limited as long as it is three or more, but is preferably five or more, and is preferably obtained at equal intervals in the longitudinal direction of the honeycomb block. This is because a more accurate distribution of the center of the cross section curve perpendicular to the longitudinal direction of the honeycomb block can be obtained.

Then, in the cross-sectional curve is the distance to the center c2-1 and the least square straight line A in r _1, the center distance between the c2-2 and the least square straight line in the cross-sectional curve B r _2, and the cross-sectional curve C The distance r ₃ between the center c2-3 and the least square line is obtained, respectively. These r ₁ to r ₃ are determined by the length of the vertical line drawn from the centers c2-1 to c2-3 with the least square line.

Next, the distance D3-1 from the center c2-1 in the cross-sectional curve A to the outermost point of the cross-sectional curve A, the distance D3-2 from the center c2-2 in the cross-sectional curve B to the outermost point of the cross-sectional curve B, and the cross-section The distance D3-3 from the center c2-3 in the curve C to the outermost point of the cross-sectional curve C is obtained, respectively.

In the honeycomb structured body, the ratio of the distance between the center and the center of the least square line drawn by the least square method based on the positional data of the center with respect to the distance between the center and the outermost point of the cross-sectional curve is 0.1 to 3%. It is desirable to be at.

That is, in the honeycomb structural body 60, it is preferable that r ₁ for D3-1, r ₂ for D3-2, and r ₃ for D3-3 are each 0.1 to 3%. If it is less than 0.1%, the honeycomb block may have little distribution in the center of the cross-section curve perpendicular to the longitudinal direction, and the extrusion strength of the honeycomb structure may be lowered. When the inequality increases, for example, when the honeycomb structure is installed in the casing through a mat-like holding seal for use as an exhaust gas purifying apparatus, it may cause shaking due to use, and thus, the extrusion strength is lowered and the durability is inferior. have. In addition, the installation itself in the casing becomes difficult.

The other configuration of the micro-curved honeycomb structural body, the material constituting the honeycomb structural body, and the like may be the same as those described as the aggregate honeycomb structural body in the honeycomb structural body of the present invention described above. Detailed description will be omitted.

In addition, the center mismatched honeycomb structure and the finely curved honeycomb structure can also function as the honeycomb filter for purification of exhaust gas or the catalytic converter similarly to the honeycomb structure of the present invention described above.

As described above, the minute curved honeycomb structural body has irregularities formed on the outer circumferential surface of the honeycomb block, the center of the cross-sectional curve drawn by the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block, and the length of the honeycomb block. Since the center of the other cross-sectional curve drawn by the contour of the cross section perpendicular to the direction does not exist on a straight line parallel to the longitudinal direction of the honeycomb block, and its distribution is controlled in a predetermined range, durability is excellent with extrusion strength. .

Thus, for example, even when the micro-curved honeycomb structured body is installed in the casing through a mat-like holding sealing material or the like as the exhaust gas purifying device, and the pressure by the exhaust gas or the like is applied from one end surface side of the honeycomb structured body, the honeycomb structured body is provided. Is hardly displaced in the casing.

Such a finely curved honeycomb structure can also be suitably used as a catalytic converter or the like.

Next, the manufacturing method of the honeycomb structural body of this invention is demonstrated.

The honeycomb structural body of the present invention can be produced, for example, by the following production method (first production method).

The 1st manufacturing method includes the process of performing the outer peripheral part process of the ceramic dried body obtained by drying the ceramic molded object containing the ceramic material which comprises the said honeycomb unit, and manufacturing several types of ceramic dried bodies from which the shape differs. It is characterized by.

In the first production method, first, a mixed composition containing a ceramic material constituting the honeycomb unit is produced, and a ceramic molded body manufacturing step of manufacturing a prismatic ceramic molded body is performed by extrusion molding using the mixed composition. .

As said mixed composition, the inorganic particle, the said inorganic fiber, and / or a whisker must be included necessarily, In addition to these, the inorganic binder, organic binder, a dispersion medium, the shaping | molding adjuvant, etc. which were mentioned above can be used suitably.

Methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, polyethylene glycol, a phenol resin, an epoxy resin etc. are mentioned as said organic binder. These may be used independently and may use 2 or more types together.

As for the compounding quantity of the said organic binder, 1-10 weight part is preferable with respect to a total of 100 weight part of the said inorganic particle, inorganic fiber, whisker, and an inorganic binder.

Although it does not specifically limit as said dispersion medium, For example, water, organic solvents, such as benzene, alcohol, such as methanol, etc. are mentioned. The dispersion medium is blended in an appropriate amount such that the viscosity of the mixed composition is within a certain range.

Although it does not specifically limit as said molding auxiliary, For example, ethylene glycol, dextrin, fatty acid, fatty acid soap, polyalcohol, etc. are mentioned.

In the method for producing a honeycomb structural body, a mixed composition is prepared by mixing these raw materials with a mixer, an attritor, or the like, or by sufficiently kneading with a kneader or the like.

Moreover, it is preferable that the porosity of the honeycomb structural body after manufacture of the said mixed composition will be about 20 to 80%.

By performing extrusion molding using the mixed composition, a columnar molded body having a columnar shape and a plurality of cells arranged in the longitudinal direction with cell walls interposed therebetween is produced, and the molded body is cut to a predetermined length to FIG. 2 (a). A prismatic ceramic shaped body of approximately the same shape as the honeycomb unit 20 shown is produced.

Subsequently, the ceramic molded body is dried using a microwave dryer, a hot air dryer, a dielectric dryer, a reduced pressure dryer, a vacuum dryer, a freeze dryer, or the like to obtain a ceramic dried body.

Subsequently, the outer peripheral part process of the said ceramic dry body is performed and the outer peripheral part process process which manufactures the ceramic dry body of several types from which the shape differs is performed. Specifically, a part of the part which becomes a cell of substantially the same shape as the honeycomb unit 200 and 210 shown to FIG.2 (b) and 2 (c) is erased, and the remainder part is exposed to the outer peripheral surface, and an unevenness | corrugation is made. The formed ceramic dried body is prepared.

Through the firing process described later, a plurality of honeycomb units having different shapes are manufactured, and in the following block manufacturing process, a plurality of honeycomb units having different shapes are bonded and bonded together, and the roughness having irregularities on the outer circumferential surface thereof is obtained. A cylindrical honeycomb block is produced.

In the outer peripheral part processing method of the said ceramic dry body, it does not specifically limit as a method of manufacturing several types of ceramic dry bodies from which the shape differs, For example, a grindstone is formed in one end as disclosed in Unexamined-Japanese-Patent No. 2000-001718. And cutting a cylindrical cutting member whose inner diameter is approximately the same as the outer diameter of the honeycomb block while cutting a portion of its outer peripheral portion from one end face side of the prismatic ceramic dry body while rotating the center of the cylinder as the rotation axis. Direction, and a cutting member in which a grindstone is disposed in a portion including an outer circumferential portion of a disc-shaped base metal portion disclosed in Japanese Patent Application Laid-Open No. 2000-001719, while rotating the center of the base metal portion as a rotation axis, and having a prismatic shape. Contacting the outer circumferential portion of the ceramic dried body to dry the cutting member Movement in the longitudinal direction of, by and a method for cutting a portion of the outer peripheral portion.

In the outer peripheral portion processing step, the size of the irregularities formed on a portion of the outer peripheral surface of the ceramic dry body is appropriately determined according to the size of the honeycomb structure of interest, honeycomb block manufactured through a honeycomb block manufacturing process to be described later The size of the irregularities formed on the outer circumferential surface of is adjusted to be equal to the size of the irregularities formed on the outer circumferential surface of the honeycomb block in the honeycomb structural body of the present invention described above.

In addition, in the case of performing the coating layer forming step described later, the unevenness of the unevenness formed on the outer circumferential surface of the honeycomb block manufactured in the honeycomb block manufacturing process is larger than the unevenness formed on the outer circumferential surface of the honeycomb block in the honeycomb structural body of the present invention. May be formed on the outer circumferential surface of the ceramic dried body, and the size of the irregularities formed on the outer circumferential surface may be adjusted by the coating layer formed on the outer circumferential surface of the honeycomb block in the subsequent coating layer formation process.

Subsequently, a plurality of kinds of ceramic dry bodies having different shapes are heated to remove the binder contained in the ceramic dry bodies, and a degreasing treatment is performed to form a ceramic degreasing body.

The degreasing step of the ceramic dried body is usually carried out by attaching the ceramic dried body to a degreasing jig and then carrying it into a degreasing furnace and heating at about 400 ° C. for about 2 hours. As a result, most of the binder and the like are volatilized and decomposed and lost.

Further, the ceramic degreasing body is baked by heating at 600 to 1200 ° C, and a firing step of sintering ceramic powder to produce a honeycomb unit is performed.

When the firing temperature is less than 600 ° C., the sintering of ceramic particles and the like does not proceed, and the strength as a honeycomb structure may be lowered. When the firing temperature exceeds 1200 ° C., the sintering of the ceramic particles and the like proceeds excessively and the specific surface area per unit volume becomes small. This is because the catalyst component may not be sufficiently dispersed in the catalyst component when the catalyst is supported.

Moreover, more preferable baking temperature is 600-1000 degreeC.

Moreover, in the series of processes from a degreasing process to a baking process, it is preferable to put the said ceramic dry body on a baking jig, and to perform a degreasing process and a baking process as it is. This is because the degreasing step and the firing step can be efficiently performed, and the ceramic dry body can be prevented from being damaged during replacement.

Subsequently, the honeycomb block manufacturing process which manufactures the substantially cylindrical honeycomb-shaped block by combining several types of honeycomb unit from which the said shape differs through a sealing material (adhesive) paste is performed.

In this honeycomb block manufacturing process, a sealant (adhesive) paste layer having a predetermined thickness is applied by applying a sealant (adhesive) paste to approximately the entire surface of two sides of the honeycomb unit using, for example, a brush, a squeegee, a roll, and the like. To form.

Further, after the sealing material (adhesive) paste layer is formed, the steps of adhering the other honeycomb units are repeated to produce a cylindrical ceramic laminate such as the honeycomb structure 10 shown in FIG. 1 at a predetermined size. .

Here, the number of honeycomb units adhered through the sealing material (adhesive) paste layer is appropriately determined in consideration of the shape and size of the intended honeycomb block.

In addition, the honeycomb unit of the shape shown to FIG.2 (b) and 2 (c) is used in the vicinity of the outer peripheral part of the said ceramic laminated body, and shown in FIG.2 (a) to the part other than the vicinity of the outer peripheral part of the said ceramic laminated body. Preference is given to using honeycomb shaped units. This is for producing a cylindrical honeycomb block. In the ceramic laminate, unevenness is formed by cutting away a part of the cell and exposing the remaining part on the outer peripheral surface thereof.

Subsequently, the ceramic laminate thus produced is heated, for example, at 50 to 150 ° C. under a condition of 1 hour to dry and cure the sealing material (adhesive) paste layer to form a sealing material layer (adhesive layer), and to form a honeycomb. The unit produces a plurality of honeycomb blocks bound together via a sealant layer (adhesive layer) to produce an aggregate honeycomb structure.

As a material which comprises the said sealing material (adhesive) paste, the material similar to the material which comprises the sealing material layer (adhesive layer) demonstrated by the honeycomb structural body of 1st this invention is mentioned.

The sealing material layer (adhesive layer) formed by the sealing material (adhesive) paste may further contain a small amount of water, a solvent, and the like. However, such moisture, a solvent, and the like are usually heated after applying the sealing material (adhesive) paste. Almost scattered.

In the said manufacturing method, after manufacturing the said honeycomb block, the sealing material layer (coating layer) formation process of forming a sealing material layer (coating layer) in the outer peripheral surface of the said honeycomb block is performed.

Furthermore, after forming a sealing material layer (coating layer), the outer peripheral part is processed to control the size of the unevenness formed on the outer peripheral surface of the honeycomb structural body.

Although it does not specifically limit as a material which comprises the said sealing material layer (coating layer), It is preferable to contain heat resistant materials, such as an inorganic fiber and an inorganic binder. The sealing material layer (coating layer) may be made of the same material as the sealing material layer (adhesive layer) described above.

It does not specifically limit as a method of forming the said sealing material layer (coating layer), For example, using the support member provided with a rotation means, the said honeycomb block is axially supported and rotated in the direction of the rotation axis, and the said sealing material layer (coating layer) The mass of the sealing material (coating) paste to be adhered to the outer peripheral portion of the rotating honeycomb block. Further, the sealing material (coating material) paste is extended using a plate member or the like to form a sealing material (coating material) paste layer, and then dried at a temperature of 120 ° C. or higher, for example, to evaporate moisture to seal the sealing material layer on the outer peripheral portion of the honeycomb block. The method of forming a (coating layer) can be used.

As described above, according to the first manufacturing method, since cutting is not performed on the ceramic, which is a brittle material, irregularities are formed on the outer circumferential surface of the honeycomb block, and a plurality of honeycomb units are formed. The honeycomb structured body including the honeycomb block of the structure couple | bonded through the sealing material layer (adhesive layer) can be manufactured.

Further, according to the first manufacturing method, the sealing material layer for adjusting the size of the unevenness formed on a part of the outer peripheral surface of the ceramic dried body in the outer peripheral part processing step or forming the outer peripheral surface of the honeycomb block in the sealing material layer (coating layer) forming step. By adjusting the thickness of the (coating layer), the honeycomb structural body of the present invention can be produced in which the size of the unevenness formed on the outer circumferential surface of the honeycomb block is controlled within a predetermined range.

In the first manufacturing method, a plurality of kinds of ceramic dry bodies having different shapes are prepared in advance in the outer peripheral part processing step, and when the degreasing step and the firing step are performed using such ceramic dry parts, some warp is produced in the honeycomb unit to be manufactured. This happens. Therefore, the honeycomb structured body produced while controlling the bending direction or size of the honeycomb unit by the thickness of the sealing material layer (adhesive layer) or the like is the center of the cross-sectional curve formed by the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block. And the center of another cross-sectional curve formed by the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block does not exist on a straight line parallel to the longitudinal direction of the honeycomb block. That is, according to a 1st manufacturing method, a center mismatch type honeycomb structure can be manufactured.

Moreover, the honeycomb structural body of this invention can also be manufactured using the manufacturing method (2nd manufacturing method) demonstrated below.

The second manufacturing method includes a step of producing a ceramic molded body having a plurality of types of cross-sectional shapes by an extrusion molding method.

In the second manufacturing method, first, a mixed composition containing a ceramic material constituting the honeycomb unit is produced, and a ceramic molded body manufacturing step of manufacturing a ceramic molded body having a plurality of cross-sectional shapes is performed using the mixed composition.

That is, in the second manufacturing method, the mixed composition is extrusion molded to produce a prismatic ceramic molded body and a ceramic molded body having irregularities formed on a part of its outer peripheral surface.

Here, the unevenness of the ceramic molded body in which the unevenness is formed on a part of the outer circumferential surface is, for example, a part of the cell is cut off and removed as shown in the honeycomb units 20, 200, and 210 shown in Figs. The remaining portion may be exposed on the outer circumferential surface, but may be formed stepwise, such as a honeycomb unit constituting the vicinity of the outer circumferential portion of the honeycomb structural body 50 shown in Fig. 5A.

The size of the irregularities formed on a part of the outer circumferential surface of the ceramic formed body is appropriately determined according to the size of the desired honeycomb structured body, but in the present manufacturing method, the size is controlled to be the same as the irregularities formed on a part of the outer circumferential surface of the ceramic dried body. It is desirable to. By the second manufacturing method, the honeycomb structural body of the present invention having excellent isotactic strength can be produced.

Thereafter, using the manufactured ceramic molded body having a plurality of cross-sectional shapes, a drying step, a degreasing step, a firing step, and a honeycomb block manufacturing step similar to those of the first manufacturing method are performed, and a sealing material layer (coating layer) is necessary. By carrying out the forming step, a honeycomb structural body with irregularities formed on the outer circumferential surface of the honeycomb block can be produced.

As described above, according to the second manufacturing method, since no machining is performed on the ceramic, which is a brittle material, irregularities are formed on the outer circumferential surface of the honeycomb block, and a plurality of honeycomb units are formed. The honeycomb structured body including the honeycomb block of the structure couple | bonded through the sealing material layer (adhesive layer) can be manufactured.

In addition, according to the second manufacturing method, the sealing material for adjusting the size of the unevenness formed in a part of the outer peripheral surface of the ceramic molded body in the ceramic molded body manufacturing step or forming the outer peripheral surface of the honeycomb block in the sealing material layer (coating layer) forming step. By adjusting the thickness of the layer (coating layer), the honeycomb structural body of the present invention can be produced in which the size of the unevenness formed on the outer circumferential surface of the honeycomb block is controlled in a predetermined range.

In the second manufacturing method, a plurality of types of ceramic molded bodies having different shapes are produced in advance in the ceramic molded body manufacturing step, and the honeycomb unit is bent in the honeycomb unit to be manufactured by performing a drying step, a degreasing step, and a firing step using the ceramic molded body. This happens. Therefore, the honeycomb structured body produced while controlling the bending direction or size of the honeycomb unit by the thickness of the sealing material layer (adhesive layer) or the like is the center of the cross-sectional curve formed by the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block. And the center of another cross-sectional curve formed by the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block does not exist on a straight line parallel to the longitudinal direction of the honeycomb block. That is, according to the 2nd manufacturing method, a finely curved honeycomb structure can be manufactured preferably.

The manufacturing method of the honeycomb structural body described so far is a manufacturing method of a collective honeycomb structural body, As mentioned above, the honeycomb structural body of this invention may be an integral honeycomb structural body, In this case, in the manufacturing method mentioned above, a ceramic material After preparing a mixed composition comprising a, by extrusion molding into a predetermined shape to further dry, degreasing, and firing to form an integral honeycomb block, and then to form a predetermined sealing material layer (coating layer) in the outer peripheral portion can do.

Next, the exhaust gas purification apparatus of this invention is demonstrated.

The exhaust gas purifying apparatus of the present invention is characterized in that the honeycomb structural body of the present invention described above is provided in a casing which connects to the exhaust passage of the internal combustion engine through the mat-like holding sealing material layer.

FIG. 7 is a cross-sectional view schematically showing an example of the exhaust gas purifying apparatus of the present invention, and FIG. 8 (a) shows an example of a honeycomb structural body wound and adhered with a mat-like holding sealing material in the exhaust gas purifying apparatus shown in FIG. Fig. 8 (b) is a partially enlarged cross-sectional view thereof.

As shown in FIG. 7, the exhaust gas purifying apparatus 70 of the present invention mainly includes a honeycomb structural body 80, a casing 71 covering the outside of the honeycomb structural body 80, and a honeycomb structural body 80. An inlet pipe 74 connected to an internal combustion engine, such as an engine, is connected to an end of the mat-like holding and sealing material 72 disposed between the casings 71 and an exhaust gas of the casing 71 is introduced. The discharge pipe 75 connected to the outside is connected to the other end of the casing 71. In addition, the arrow in FIG. 7 shows the flow of exhaust gas.

In addition, in the exhaust gas purification apparatus 70 of the present invention, the honeycomb structural body 80 may be a honeycomb structural body of the present invention as shown in Figs. 1, 3 and 5, as shown in Fig. 6. It may also be a honeycomb structural body of the second invention.

In the exhaust gas purifying apparatus 70 of the present invention, the cell wall of the honeycomb structural body 80 functions as a so-called catalytic converter for purifying CO, HC, NOx, and the like in the exhaust gas on the cell wall of the honeycomb structural body 80. The surface and pores of the catalyst carry a catalyst capable of purifying CO, HC, NOx, and the like in the exhaust gas.

As said catalyst, noble metals, such as platinum, palladium, rhodium, an alkali metal, alkaline earth metal, an oxide, etc. are mentioned, for example. These may be used independently and may use 2 or more types together.

That is, in this case, in the exhaust gas purification device 70, the exhaust gas discharged from an internal combustion engine such as an engine is introduced into the casing 71 through the introduction pipe 74 and the honeycomb structural body 80 (catalyst converter) When passing through the cell, CO, HC, NOx, and the like in the exhaust gas are purified by contact with the catalyst and then discharged to the outside through the discharge pipe 75.

In the exhaust gas purifying apparatus 70 of the present invention, the honeycomb structural body 80 (honeycomb block) has a sealing material layer (coating material layer) 701 at an uneven portion formed on its outer circumferential surface, as shown in Fig. 8B. ) Is formed, and irregularities are also provided on the outer circumferential surface thereof and are provided in the casing 71 through the mat-like holding seal 72.

As the honeycomb structural body 80 is held by the mat-like holding seal 72 as described above, a so-called anchor effect is obtained between the honeycomb structural body 80 and the mat-shaped holding seal 72 so that the honeycomb structure is in use. Position shift does not occur between the structure and the mat-like holding seal, and the durability of the exhaust gas purification device of the present invention can be improved, and exhaust gas leaks from the outer peripheral portion of the honeycomb structure 80. It can also be prevented.

In particular, when the honeycomb structured body in the exhaust gas purifying apparatus of the present invention is a center mismatched honeycomb structure or a micro curved honeycomb structure, the center mismatched honeycomb structure or the micro curved honeycomb structured body as described above is Since the extrusion strength is very excellent, even when a large pressure is applied to one end surface of the honeycomb structured body by the exhaust gas flowing into the casing from the introduction pipe, the honeycomb structured body does not deviate from the flow direction of the exhaust gas, The exhaust gas purification device is very durable.

8 (b), the unevenness formed on the outer circumferential surface of the honeycomb block of the honeycomb structural body 80 is stepped like the honeycomb structural body 50 shown in FIG. As well as the irregularities formed on the outer circumferential surface of the block, as shown in FIG. 2 or FIG. 3, some of the cells constituting the honeycomb block may be deleted and the remaining portion may be exposed on the outer circumferential surface.

The mat-like holding seal member 72 functions as a heat insulating material for holding and fixing the honeycomb structured body 80 in the casing 71 and at the same time keeping the honeycomb structured body 80 in use.

It does not specifically limit as a material which comprises this mat-like holding | maintenance sealing material 72, For example, Inorganic fibers, such as crystalline alumina fiber, alumina-silica fiber, mullite, a silica fiber, and these inorganic fibers are included at least 1 type. Fiber, and the like.

In addition, non-expandable mats substantially free of vermiculite and low-expansion mats containing a small amount of vermiculite may be mentioned, and non-expandable mats substantially free of vermiculite are preferable.

An expanded ceramic fibrous mat is particularly preferable as the mat-like holding sealant.

In addition, it is preferable that the mat-like holding | maintenance sealing material 72 contains alumina and / or silica. This is because the heat resistance and durability of the mat-like holding seal 72 become excellent. In particular, it is preferable that the mat-like holding sealing material 72 contains 50% by weight or more of alumina. This is because the elastic force increases even at a high temperature of about 900 to 950 ° C., and thus the force for holding the honeycomb structural body 80 increases.

Moreover, it is preferable that the needle | punching punching process is given to the mat-like holding | maintenance sealing material 72. This is because the fibers constituting the holding sealing material 72 are entangled with each other and the elastic force is increased, and the force for holding the honeycomb structural body 80 is improved.

It is preferable that the mat-shaped holding | maintenance sealing material 72 which consists of such a material is wound so that the substantially whole outer peripheral surface of the honeycomb structural body 80 may be covered as shown to FIG. 8 (a). This is because the honeycomb structural body 80 can be fixed uniformly and the holding stability of the honeycomb structural body 80 is excellent.

As described above, the exhaust gas purifying apparatus of the present invention is provided in the casing in a state where the mat-shaped holding sealant is filled in the recess of the outer circumferential surface of the honeycomb block of the honeycomb structural body of the present invention. The so-called anchor effect is generated between the mat-like holding seal and the holding stability of the honeycomb structural body is excellent.

Therefore, in the exhaust gas purifying apparatus of the present invention, the fixing force of the honeycomb structural body by the mat-like holding seal material is reduced or the position of the honeycomb structural body is reduced due to the pressure of the exhaust gas flowing into the casing during use, the temperature of the honeycomb structural body, or the like. A shift does not generate | occur | produce and it becomes the thing excellent in durability.

<Example>

Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to these Examples.

<Example 1>

(1) 40 weight% of (gamma) -alumina particles (average particle diameter: 2 micrometers), 10 weight% of silica-alumina fibers (average fiber diameter: 10 micrometers, average fiber length: 100 micrometers, aspect ratio 10), silica sol (solid concentration: 30 weight%) 50 weight% was mixed, 6 weight part of methylcelluloses, a plasticizer, and a lubricating agent were added little by little as an organic binder with respect to 100 weight part of the obtained mixture, and also it mixed and kneaded and obtained the mixed composition. Next, this mixed composition was extruded by an extrusion molding machine to obtain an untreated molded body. This untreated molded body had a cell density of 31 columns / cm ² in a columnar shape (34.3 mm × 34.3 mm × 300 mm), and a cell wall thickness of 0.35 mm.

(2) Subsequently, the unprocessed molded body is sufficiently dried using a microwave dryer and a hot air dryer to form a ceramic dried body, and then the outer peripheral portion of the outer peripheral portion is formed by using a cutting member in which a grindstone is disposed on the portion including the outer peripheral portion of the base metal portion. The outer periphery process which cuts a part was performed, and as shown to FIG.2 (b) and FIG.2 (c), the ceramic dry body which produced the part of each pillar was cut off and exposed a part of the through hole to the part was manufactured.

(3) It degreased | maintained at 400 degreeC for 2 hours. Then, it baked and hold | maintained at 800 degreeC for 2 hr, and obtained the several types of honeycomb unit from which the shape differs.

At this time, the outer circumferential portion of the ceramic dried body was held and fixed with a fixing jig having a holding part having a shape substantially the same as that of the ceramic dried body so that warpage did not occur in the honeycomb unit to be manufactured.

Moreover, the electron microscope (SEM) photograph of the cell wall of a honeycomb unit is shown in FIG.

This honeycomb unit was found to be oriented with silica-alumina fibers along the extrusion direction of the raw material paste.

(4) Next, 29 weight% of (gamma) -alumina particles (average particle diameter: 2 micrometers), 7 weight% of silica-alumina fibers (average fiber diameter: 10 micrometers, average fiber length: 100 micrometers), silica sol (solid weight: 30 weight%) 34 Weight%, 5 weight% of carboxymethylcellulose, and 25 weight% of water were mixed and it was set as the heat resistant sealing material paste. The sealing material paste was used to bind a plurality of honeycomb units of a plurality of types, and then the sealing material (adhesive) paste was dried to prepare a cylindrical honeycomb block.

The honeycomb block thus produced was 0.0 mm when M2 was obtained by the method described in the honeycomb structural body of the present invention in the above-described embodiment using a three-dimensional measuring instrument (manufactured by Mitsudo Toyo, BH-V507). .

Therefore, cutting was applied to the outer circumferential surface of the honeycomb block to make M2 = 0.5 mm.

(5) Next, a plurality of silicon carbides are formed on the outer circumferential surface of the honeycomb block by forming a sealing material layer (coating layer) having the same composition as the sealant (adhesive) paste and having a shape corresponding to the irregularities formed on the outer circumferential surface of the honeycomb block. The honeycomb unit was bonded through a sealing material layer (adhesive layer), and a honeycomb structural body including a honeycomb block having irregularities formed on its outer circumferential surface was manufactured.

The honeycomb structured body thus produced was similarly obtained with M3 in the same manner as the honeycomb block by using a three-dimensional measuring device.

Thereafter, the sealing material layer (coating layer) was subjected to processing so as to provide unevenness to the honeycomb structural body, and M1 was 0.3 mm.

In addition, with respect to the honeycomb structural body manufactured in the present embodiment, the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb unit is 11.8 cm ² , and the sum of the cross-sectional areas in the cross section perpendicular to the longitudinal direction of the honeycomb structural body is It occupies 93.5% of the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb structural body.

<Examples 2 to 11, Reference Examples 1 to 4 and Comparative Examples 1 to 12>

In the same manner as in Example 1, by processing the obtained honeycomb block or honeycomb structural body to adjust the unevenness of the surface, a honeycomb structural body (honeycomb block) having M1 and M2 values shown in Table 1 below was produced, respectively. It was.

In Examples 10 to 11, as a sealant (adhesive) paste, 30 wt% of alumina fibers having a fiber length of 20 μm, 21 wt% of silicon carbide particles having an average particle diameter of 0.6 μm, 15 wt% of a silica sol, and carboxymethylcellulose 5.6 A honeycomb block was manufactured and processed in the same manner as in Example 1 except that a heat resistant sealing material (adhesive) paste containing 28% by weight and water was used, and a honeycomb structural body was produced and processed.

In Comparative Example 1, a honeycomb structural body was produced in the same manner as in Example 1 except that the obtained honeycomb block and the honeycomb structural body were not processed.

[Evaluation Test 1-Thermal Shock Test]

The honeycomb structural bodies according to Examples 1 to 11, Reference Examples 1 to 4 and Comparative Examples 1 to 12 were placed in an electric furnace, heated to a target temperature at 20 ° C./min, maintained at 600 ° C. or 800 ° C. for 1 hour, and then returned to room temperature. Air cooled. The presence or absence of cracks at this time was visually confirmed. The results are shown in Table 1 below.

[Evaluation Test 2-Measurement of Extrusion Strength]

A metal cylinder wound around an honeycomb structured body according to Examples 1 to 11, Reference Examples 1 to 4, and Comparative Examples 1 to 12 with a non-expandable alumina fiber mat (MAFTEC manufactured by Mitsubishi Chemical Corporation, MAFTEC) having a thickness of 7 mm. After being inserted into the case, the strength at the time of exiting the extrusion load by Instron was measured. The results are shown in Table 1.

As is clear from the results shown in Table 1, the extruded loads of the honeycomb structural bodies according to Examples 1 to 11 are all larger than 15 kg, and the honeycomb structural bodies according to Examples 1 to 11 are honeycomb even when thermal shock is applied. No crack or the like occurred near the outer circumferential surface of the structure.

On the other hand, in the honeycomb structural bodies of Comparative Examples 1 to 12, the extrusion load was low, and the thermal shock was weak even when the extrusion load was high.

<Example 12>

Subsequently, a honeycomb structural body was produced in which the position of the center c2 of the honeycomb block and the center c1 of the honeycomb structural body were shifted.

Specifically, a honeycomb structural body of M2 = 0.5 mm was produced in the same manner as in Example 1, and then, a honeycomb structural body of M2 = 0.5 mm was manufactured by changing the thickness balance of the sealing material layer (coating layer).

<Examples 13 to 19 and Reference Examples 5 to 6>

By changing the thickness of the sealing material layer (coating layer) as in the case of Example 12, a honeycomb block and honeycomb structural body having M1, M2, and c1-c2 described in Table 2 were prepared. In Examples 18 to 19, honeycomb block and honeycomb structural bodies having M1, M2 and c1-c2 shown in Table 2 were prepared using the same sealing material (adhesive) paste as in Examples 10 to 11.

The honeycomb structural bodies of Examples 12 to 19 and Reference Examples 5 to 6 were wound with an alumina mat and placed in a metal case in the same manner as in Examples 1 to 11, and then extruded.

Furthermore, after heat-processing the obtained honeycomb structural body at 600 degreeC for 30 hours, the extrusion load was measured similarly. In addition, the strength reduction rate after heat treatment shown in Table 2 represents the ratio of the extrusion load after heat treatment to the extrusion load before heat treatment as a percentage.

As shown in Table 2, in Examples 12 to 19, the strength reduction rate was 60% or more, that is, the extrusion strength was 60% or more even after the heat treatment. In Reference Examples 5 and 6, the strength reduction rate was less than 60%.

Moreover, when manufacturing the honeycomb structural body which concerns on Examples 1-19, Reference Examples 1-6, and Comparative Examples 1-12, there existed no defects, a crack, etc. in the outer peripheral surface of a honeycomb block.

Example 20

(1) 40 weight% of (gamma) -alumina particles (average particle diameter: 2 micrometers), 10 weight% of silica-alumina fibers (average fiber diameter: 10 micrometers, average fiber length: 100 micrometers, aspect ratio 10), silica sol (solid weight: 30 weight%) 50 weight% was mixed, 6 weight part of methylcelluloses, a plasticizer, and a lubricating agent were added little by little as an organic binder with respect to 100 weight part of the obtained mixture, and also it mixed and kneaded and obtained the mixed composition. Next, this mixed composition was extruded by an extrusion molding machine to obtain an untreated molded body.

One of these molded bodies is a prismatic pillar which is almost the same as the honeycomb unit 20 shown in Fig. 2 (a), its size is 35 mm x 35 mm x 300 mm, the cell density is 31 / cm ² , and the cell wall thickness is 0.35 mm.

In addition, a portion of the prisms as shown in Figs. 2 (b) and 2 (c) are cut and removed using the mixed composition, and the honeycomb units 200 and 210 having the through holes exposed to the portions are roughly removed. Ceramic molded bodies of the same shape were also produced.

(2) Subsequently, the untreated molded body was sufficiently dried using a microwave drier and a hot air drier to obtain a ceramic dried body, and then degreased by maintaining at 2 hours at 400 ° C. Then, it baked and hold | maintained at 800 degreeC for 2 hr, and obtained the several types of honeycomb unit from which the shape differs.

In the process of manufacturing a honeycomb unit from the said ceramic dry body, curvature generate | occur | produced in the honeycomb unit obtained by holding and fixing a ceramic molded body by the fixing jig | tool which remained in a bending state especially.

(3) Next, 29 wt% of γ-alumina particles (average particle diameter 2 µm), 7 wt% silica-alumina fiber (average fiber diameter 10 µm, average fiber length 100 µm), silica sol (solid concentration 30 wt%) 34 Weight%, 5 weight% of carboxymethylcellulose, and 25 weight% of water were mixed and it was set as the heat resistant sealing material paste. The sealing material paste was used to bind a plurality of honeycomb units of a plurality of types, and then the sealing material (adhesive) paste was dried to prepare a cylindrical honeycomb block.

(4) Subsequently, a large number of silicon carbides are formed on the outer circumferential surface of the honeycomb block by forming a sealant layer (coating layer) having the same composition as the sealant (adhesive) paste and having a shape corresponding to the irregularities formed on the outer circumferential surface of the honeycomb block. The honeycomb unit including the honeycomb unit was bound by a sealing material layer (adhesive layer), and a honeycomb structural body including a honeycomb block having irregularities formed on its outer circumferential surface was manufactured.

<Examples 21 to 27 and Reference Examples 7 to 8>

By causing the honeycomb unit to warp in the same manner as in Example 20, a deviation from the least square line was produced in the honeycomb structural body as described in Table 3 below. In Examples 26 to 27, as the sealant (adhesive) paste, 30 wt% of alumina fibers having a fiber length of 20 μm, 21 wt% of silicon carbide particles having an average particle diameter of 0.6 μm, 15 wt% of silica sol, and 5.6 wt% of carboxymethylcellulose were used. Except having used the heat-resistant sealing material (adhesive) paste containing% and 28.4 weight% of water, the honeycomb structural body as described in Table 3 was produced similarly to Example 20 with the deviation from a least square line.

Thus, the honeycomb structural bodies according to Examples 20 to 27 and Reference Examples 7, 8 manufactured in this manner were used in the above-described embodiment using a three-dimensional measuring machine (BH-V507 manufactured by Mitsutoyo Co., Ltd.). The ratio of the distance between the center and the least-squares curve with respect to the distance between the center of the cross-sectional curve perpendicular to the longitudinal direction of the honeycomb block and the outermost point of the cross-sectional curve by the method described in It was 0.1 about 5 places parallel to the longitudinal direction of the said honeycomb block, and equally spaced.

The honeycomb structural bodies of Examples 20 to 27 and Reference Examples 7 to 8 were similarly wound with an alumina mat and placed in a metal case, and then extruded.

Furthermore, after heat-processing it at 600 degreeC for 30 hours in the electric furnace, extrusion load was similarly measured.

As shown in Table 3, in Examples 20 to 27, the strength reduction rate was 60% or more. In Reference Examples 7 to 8, the strength reduction rate was less than 60%.

The honeycomb structural body of the present invention has high strength against thermal shock (large durability), and is excellent in durability without cracking or breaking even when high pressure is applied from its outer peripheral surface.

In addition, since the honeycomb unit comprises inorganic particles, inorganic fibers and / or whiskers, the specific surface area is improved by the inorganic particles, and the strength of the honeycomb unit is improved by the inorganic fibers and / or whiskers. The honeycomb structural body of the present invention can be particularly preferably used as a catalytic converter.

In addition, in the honeycomb structure in which the center c1 and the center c2 do not coincide (herein referred to as the center mismatched honeycomb structure), the extrusion strength is high, and the exhaust gas purifier is installed in the casing through a mat-like holding seal or the like. Even when used as a catalytic converter or a honeycomb filter for a long time (when subjected to thermal shock), it is excellent in durability without shaking.

Further, when three or more points of the center c2 of the least square curve are obtained in the longitudinal direction of the honeycomb block, a honeycomb structure in which these center c2 does not exist on a straight line parallel to the length direction of the honeycomb block, or the minimum When the center c1 of the squared curve is obtained at least three points in the longitudinal direction of the honeycomb structured body, the honeycomb structured body in which the center c1 does not exist on a straight line parallel to the longitudinal direction of the honeycomb structured body (finely curved in this specification) Honeycomb structured body) results in a honeycomb structured body having excellent extrusion strength and durability.

Since the exhaust gas purifying apparatus of the present invention is made using the honeycomb structural body of the present invention, it is possible to provide the effect of the honeycomb structural body of the present invention, and the honeycomb structural body does not shake even if used for a long time. The strength with respect to can be made excellent.

Claims (16)

It is a honeycomb structure in which the sealing material is provided in the outer periphery of the columnar honeycomb block which consists of the honeycomb unit by which the several cell was provided in the longitudinal direction parallel to the cell wall, Unevenness is formed on the outer circumferential surfaces of the honeycomb structured body and the honeycomb block, The honeycomb unit comprises inorganic particles, inorganic fibers and / or whiskers, Based on the points constituting the contour of the cross section perpendicular to the longitudinal direction of the honeycomb structured body, the least square curve is obtained by the least square method, and its center is referred to as c1, and the concentric with the center c1 of the least square curve. The distance between the minimum circumscribed curve and the center c1 is called D1, and the distance between the concentric maximum inscribed curve having the center c1 of the least square curve and the center c1 is called D2, and defined as M1 = D1-D2, 0.3 mm ≦ M1, Based on the points constituting the contour of the cross section perpendicular to the longitudinal direction of the honeycomb block, the least square curve is obtained by the least square method, the center of which is referred to as c2, and the concentric with the center c2 of the least square curve. The distance between the minimum circumscribed curve and the center c2 is called D3, and the distance between the concentric maximum inscribed curve having the center c2 of the least square curve and the center c2 is called D4, and M2 = D3-D4, and 0.5 mm ≦ Honeycomb structure, characterized in that M2≤7.0 mm. The honeycomb structured body according to claim 1, wherein said M1 is 3.0 mm or less. The honeycomb structured body according to claim 1, wherein the center c1 and center c2 do not coincide. 4. The honeycomb structural body according to claim 3, wherein the distance between the center c1 and the center c2 is 0.1 to 10.0 mm. The center c2 of any one of claims 1 to 4, wherein at least three points of the center c2 of the least-squares curve are obtained in the longitudinal direction of the honeycomb block, the center c2 is parallel to the length direction of the honeycomb block. Honeycomb structure that does not exist on a straight line. The straight line in which the center c1 is parallel to the longitudinal direction of the honeycomb structured body according to any one of claims 1 to 4, when the center c1 of the least-squares curve is found at least three points in the longitudinal direction of the honeycomb structured body. Honeycomb structure not present in the phase. The honeycomb structure according to any one of claims 1 to 4, wherein the honeycomb block is configured by binding a plurality of honeycomb units. The honeycomb structural body according to any one of claims 1 to 4, wherein a cross-sectional area in a cross section perpendicular to the longitudinal direction of the honeycomb unit is 5 to 50 cm ² . 9. The honeycomb structural body according to claim 8, wherein the sum of the cross-sectional areas in the cross section perpendicular to the longitudinal direction of the honeycomb unit occupies at least 85% of the cross-sectional area in the cross section perpendicular to the longitudinal direction of the honeycomb structural body. The honeycomb structural body according to any one of claims 1 to 4, wherein the inorganic particles are at least one member selected from the group consisting of alumina, silica, zirconia, titania, ceria, mullite and zeolite. The honeycomb type according to any one of claims 1 to 4, wherein the inorganic fiber and / or whisker is at least one member selected from the group consisting of alumina, silica, silicon carbide, silica alumina, glass, potassium titanate and aluminum borate. Structure. The honeycomb unit according to claim 1, wherein the honeycomb unit is prepared using a mixture comprising the inorganic particles and the inorganic fibers and / or whiskers and an inorganic binder, Wherein said inorganic binder is at least one member selected from the group consisting of alumina sol, silica sol, titania sol, water glass, sepiolite and attapulgite. The honeycomb structural body according to any one of claims 1 to 4, wherein the catalyst is supported. The honeycomb structured body according to claim 13, wherein said catalyst comprises at least one member selected from the group consisting of noble metals, alkali metals, alkaline earth metals and oxides. An exhaust gas purification device, wherein the honeycomb structured body according to any one of claims 1 to 4 is provided in a casing connected to an exhaust passage of an internal combustion engine via a mat-like holding seal. The exhaust gas purifying apparatus according to claim 15, wherein the mat-like holding seal is an unexpanded ceramic fibrous mat.

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